Yep, I recall when I was buying my 4BW, they had all three seat options available and I tested them each extensively back to back for over an hour. The sport bucket leather seats are the firmest. They are totally doable, look great and are excellent for the track but from a comfort perspective they are on the firm side, however, you get ventilation and massage to make up for it.
The mid-tier bucket seats are a little bit softer, I think only because they use an alcantara instead of leather on the seat cushion and where your back rests. They have the same aggressive bolstering. I think if you want the sport bucket sporty look but save a bit of money this is the sweet spot. That said, I still think they are over priced at $3k extra on the 4BW, considering you only get the front seats, back seats are still base so they are mismatched material, they have no cooling option, no leg extension like the other seats and they are not actual Recaro seats. The Recaro seats in my ZL1 were the real deal and they come standard. I feel like the base seats in the 4BW should be the mid-tier alcantara seats.
I have the base seats in my 4BW, which IMO don't look that great but they make up for in comfort. When you sit in the different seats back to back it is quite noticeable how much more cushion there is where you butt and lower back rest in the seat.